The present invention relates generally to firearms. More specifically, the present invention relates to firearms having components, such as frames and cylinders, made of scandium containing aluminum alloys, which alloys include alloying elements composed of 0.05% to 0.30% scandium and may include light weight alloying metals such as magnesium, chromium, copper and zinc, and additional rare earth elements such as zirconium, and to a method for heat treating the scandium containing aluminum alloy firearm components.
Firearm frames composed of aluminum alloys have been known for some time. The life of such firearms is limited because conventional aluminum alloys breakdown relatively fast when compared to heavier materials such as steel. Furthermore, firearms composed of heavier materials are relatively heavy. Heavier firearms are inconvenient to carry concealed.
Revolver cylinders have not been manufactured using aluminum alloys because aluminum alloys of the prior art lack the strength and endurance to hold up under the stresses caused when the revolvers are discharged. Aluminum cylinders are subject to excessive wear and/or damage upon discharge of the revolvers making the cylinders inoperable. The damage sustained includes pitting and deformation of the cylinders under the high impact upon discharge of the revolver. Cylinders have been made of heavier materials such as steel and titanium alloys; however, revolvers having conventional steel cylinders are quite heavy, and titanium alloys are very expensive.
Firearms include many components in addition to a frame and a cylinder. Such components include, but are not limited to, barrel, slide, yoke, ejector, ejector rod, sear, hammer, and trigger. These parts are typically made of heavier metals which aggregate weight, including the frame and cylinder, if present, results in an overall heavier firearm than would result if lighter alloys were used in place of the heavier metals for as many parts as possible. Each component composed of heavy alloys, such as steel and titanium, increases the overall weight of the firearm in comparison to a firearm having lighter metal components. Components requiring high durability, endurance and strength have not been made of aluminum alloys. Many such components must function with minimum degradation under high impact and radical temperature change conditions. Such conditions occur repeatedly upon discharge of the firearm. Components of the firearm must be able to withstand the abuse inflicted thereupon, and prior art aluminum alloys have been unable to meet this requirement for a large number of firearm components.
Scandium is one of the most potent alloying elements in the periodic table. When added to an aluminum alloy, scandium significantly increases strength, and reduces grain size. Furthermore, scandium is a very light metal with a much higher melting point (2806.00xc2x0 F.) than aluminum (1220.58xc2x0 F.) making such alloys more durable in that they have longer life spans, have higher strength, and are degraded less by temperature extremes. In other words, aluminum-scandium alloys can sustain a larger range of repeated abuses including more extreme temperature variations than conventional aluminum alloys. Scandium containing aluminum alloys have improved strength, improved resistance to hot cracking, and improved resistance to recrystallization. Scandium provides the highest increment of strengthening per atomic percent of any alloying element when added to aluminum. Likewise, scandium containing aluminum alloys have dramatically greater thermal stability than aluminum alloys lacking scandium. Scandium containing aluminum alloys have been used in the manufacturing of baseball bats, bicycle frames, golf clubs, various exercise equipment and aerospace applications.
Scandium containing aluminum alloys and their products are well known in the art. Aluminum and aluminum alloys of varying binary, ternary and multicomponent types having from 0.01 to about 5.0 percent by weight of scandium, which may also contain copper, magnesium, zinc, manganese, beryllium, lithium, iron, silicon, nickel, chromium, titanium, vanadium, zirconium, boron, bismuth and lead, are described in U.S. Pat. No. 3,619,181, assigned to Aluminum Company of America. U.S. Pat. No. 4,261,767, assigned to Creusot-Loire of Paris, discloses an alloy resistant to high temperature oxidation which includes chromium, nickel, iron, aluminum and at least one rare earth metal. Similarly, U.S. Pat. No. 5,059,390, assigned to Aluminum Company of America, discloses a dual-phase magnesium-based alloy consisting essentially of lithium, aluminum, a rare earth metal (preferably scandium), zinc and manganese. U.S. Pat. No. 4,261,742, assigned to Johnson, Matthey and Co., Limited, describes platinum group metalcontaining superalloys which may include 0.01 wt % to 3 wt % scandium plus chromium, aluminum, titanium, one or more of the platinum group metals, and nickel. Furthermore, U.S. Pat. No. 4,689,090, also assigned to Aluminum Company of America, describes superplastic aluminum alloys containing scandium.
Products composed of scandium containing aluminum alloys are well known in the prior art as mentioned briefly hereinabove. U.S. Pat. No. 5,597,529, assigned to Ashurst Technology Corporation (Ireland) Limited, discloses aluminum-scandium alloys which may be used in welding applications and bicycle components. U.S. Pat. No. 5,620,652, also assigned to Ashurst Technology Corporation (Ireland) Limited, discloses aluminum alloys containing scandium with zirconium additions which may be used in recreational, athletic structures and components thereof, and in certain aerospace, ground transportation, marine structures and components thereof. Neither of these applications disclose the use of scandium containing aluminum alloy firearms. The recreational equipment disclosed are made from sheets of metal instead of being extrusion molded or pressed from metal bars.
U.S. Pat. No. 5,624,632, assigned to Aluminum Company of America, shows an aluminum alloy product for use as a damage tolerant product for aerospace applications, including fuselage skin stock, which alloy may include scandium. U.S. Pat. Nos. 5,055,257 and 4,874,440, also assigned to Aluminum Company of America, describe superplastic aluminum products and alloys containing scandium. U.S. Pat. No. 5,882,449, assigned to McDonnell Douglas Corporation, discloses a process for preparing aluminum-lithium-scandium rolled sheet products. These patents do not describe lightweight firearms composed of scandium containing aluminum alloys.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a scandium containing aluminum alloy firearm solving the aforementioned problems is desired.
The present invention relates to firearms having components made of scandium containing aluminum alloys which are composed of an aluminum alloy containing alloying elements which include, in addition to aluminum, from about 0.05% to about 0.30% scandium plus light weight metals such as magnesium, chromium, copper, and zinc. The scandium containing aluminum alloy may also have zirconium as an alloying element, and may contain additional heavier metals and other rare earth metals. Preferably, the scandium containing aluminum alloy is composed of from about 0.05% to about 0.15% scandium, from about 7.5% to about 8.3% zinc, from about 1.6% to about 2.2% magnesium, from about 1.6% to about 2.0% copper, from about 0.02% to about 0.04% chromium, and from about 0.05% to about 0.15% zirconium with the balance being composed of aluminum. Incidental elements, impurities and other grain refiners may be present in the alloy as is well known in the art of metallurgy.
The scandium containing aluminum alloys used in the present invention have the following properties: yield strengths of 82 KSI to 100 KSI, tensile strengths of 88 KSI to 106 KSI, 12% to 19% elongation""s, and 7% to 10% reduction areas. Embodiments of the present invention include, but are not limited to, revolvers having scandium containing aluminum alloy frames and/or cylinders, and pistols having scandium containing aluminum alloy frames and/or slides. Further embodiments of the present invention include revolvers, pistols, air guns, gas guns, nail guns and rifles having scandium containing aluminum alloy components, which components include frames.
The present invention also contemplates a method of heat treating the scandium containing aluminum alloy firearm components to create components having the desired properties. The heat treatment follows forging or machining from bar stock. The forged components are exposed to solution heat treatment at about 875xc2x0 F. for one to two hours, followed by rapid water quench, then the components are naturally aged at ambient temperature for 24 to 72 hours (typically about 48 hours), followed by artificial aging at 250xc2x0 F. for about 24 hours, and finally allowed to air cool. The resulting components have the highly desired properties indicated. The scandium containing aluminum alloy components, plus any conventional components, are then assembled to make surprisingly lightweight but durable firearms.
An advantage of the present invention is to provide a firearm which is lightweight yet has higher yield and tensile strengths than conventional aluminum alloy firearms. In particular, revolvers having both scandium containing aluminum alloy cylinders and scandium containing aluminum alloy frames are very lightweight. Furthermore, pistols having scandium containing aluminum alloy frames and/or slides are substantially lighter than prior art pistols. Lightweight revolvers and pistols are desirable as they allow law enforcement officers to easily carry a lightweight second firearm.
It is a further advantage of the invention to provide a frame for a firearm which is lightweight yet sturdy and durable enough for use in law enforcement. Scandium containing aluminum alloy firearms are stronger and more durable than their aluminum alloy counterparts. Having strong lightweight rifles, revolvers and pistols which law enforcement officials can carry easily is desirable.
Another advantage of the invention is to provide a lightweight yet very strong cylinder which can be used with the frame of the present invention to produce an extraordinarily lightweight revolver. High caliber revolvers, such as .32 and .38 caliber, can be made with scandium containing aluminum alloy cylinders and frames thereby producing extremely lightweight yet sturdy revolvers.
Yet another advantage of the present invention is to provide lightweight firearms having increased life comparable to heavier metal alloys such as steel and titanium. Conventional aluminum alloy firearms have limited life spans compared to firearms composed of heavier metal alloys. Furthermore, firearms, such as airguns and gas guns, having increased life spans and lightweight construction are also desirable.